In this work, a series of cationic microfibrillated cellulose (CMFC) were prepared by introducing quaternary amine groups, and the sorption of a model compound for bile salts, sodium cholate, in vitro was determined. Various variables, contact time, initial concentration of sodium cholate, and the presence of salts, were investigated. Experimental results showed that the in vitro binding of sodium cholate of the CMFC was 57.95 mg/g, which was about 70% lower than that of cholestyramine. The isotherm data were analyzed according to Langmuir, Freundlich, and Tempkin models. Characteristic parameters of each model were determined. Results also showed that the Langmuir isotherm performed the best correlation for the sorption of sodium cholate onto the CMFC, and the maximum capacity, Qmax was 416.67 mg of sodium cholate per gram of CMFC. The sorption kinetics underwent a pseudo-second-order equation, suggesting a chemisorptions mechanism. Additionally, the presence of salts in the reaction system greatly prevented the CMFC sorption toward cholate, implying the interaction between sodium cholate and CMFC was electrostatic in nature. All these results support the great potential for using the CMFC as a sorbent to decrease cholesterol.